Anti-disturbance switch



' Sept. 29, 1970 M- F. SCHRICHTE ANTI-DISTURBANCE SWITCH Filed March- 12, 1969 MORETON F. SCHRICHTE ATToRNEYs 3,531,605 ANTI-DISTURBAN CE SWITCH Moreton F. Schrichte, Hamilton, Ohio, assignor to Avco Corporation, Richmond, Ind., a corporation of Delaware Filed Mar. 12, 1969, Ser. No. 806,595 Int. Cl. H01h /14 U.S. Cl. ZOO-61.45 10 Claims ABSTRACT OF THE DISCLOSURE An anti-disturbance switch has been disclosed which operates in conjunction with an electric circuit to indicate or signal that the attitude of the object or munition to which the switch is attached is being or has been disturbed or reoriented from an initial at-rest position.

BACKGROUND OF THE INVENTION This invention relates to switches or more particularly to an improved anti-disturbance switch.

Anti-disturbance switches have been used in many fields, for example: burglar alarms; auto theft alarms; money and jewel box alarms; and military uses, such as land mines and with any object desired to be bobbytrapped. The anti-disturbance switch is used to energize an alarm system or to function a detonation device.

An important feature of these switches is that they be responsive to forces of disturbance acting in any direction. It is also desirable that the switch be sensitive to magnetic fields which may be used in attempts to disarm the switch or the device in which the switch is incorporated. Numerous anti-disturbance switches have been developed, but these previously developed switches are not entirely satisfactory. The prior switches have generally been comprised of a complex assembly of elements, including combinations of balls, springs, and levers. The complexity increases the cost of manufacture and time for assembly and decreases the overall effectiveness of the switch. A further disadvantage of the prior art anti-disturbance switches is that these switches are only operative from a single condition. In other Words, the switch is normally biased open and the disturbance of the switch will close the circuit to function the circuit for its desired end eifect.

The anti-disturbance switch of the present invention is constructed with a minimum of components and as such is easily assembled and very eflicient in operation.

SUMMARY OF THE INVENTION This invention provides an improved anti-disturbance switch comprised of a minimum of component elements, yet giving the utmost in reliable efficiency. The antidisturbance switch is of simple and economical construction and is operative when the circuit path attached thereto is either in an open or closed initial state depending upon the attitude of the switch.

Other details, uses, and advantages of this invention will become apparent as the following description of the exemplary embodiment thereof presented in the accompanying drawings proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show present exemplary embodiments of this invention in which:

FIG. 1 is a side view, partially with portions thereof cut away, illustrating one exemplary embodiment of this invention;

FIG. 2 is a bottom view of the switch showing the internal member with the external member sectioned along line 22;

3,531,685 Patented Sept. 29, 1970 FIG. 3 is a sectional view of the switch taken on line 3-3 of FIG. 2;

FIG. 4 is a schematic illustration of an electrical circuit for use with the switch of this embodiment;

FIG. 5 is a side view, partially with portions thereof cut away, illustrating a switch in spherical shape; and

FIG. 6 is a sectional view of a switch having a parabolic shape.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Reference is now made to FIG. 1 of the drawings, which illustrates one exemplary embodiment of the improved anti-disturbance switch which is designated generally by the reference numeral 10. The anti-disturbance switch 10 is comprised of an inner cup-like member 12 and an outer cup-like member 14, each member having a shape generally defined as a curvilinear surface of revolution and being formed from a conducting metal, such as brass. It can be seen that the outer member 14 provides a smooth rolling surface. A rolling contact member 16 is placed for relative movement between the inner and outer members.

As best seen in FIGS. 2 and 3, the inner member is fabricated with a plurality of equi-spaced outwardly projecting protuberances or dimples 18. The protuberances extend into the space between the inner and outer members thus forming a multiplicity of paths along which the rolling contact 16 can travel. The contact member 16 is a steel ball having a diameter which will insure contact between the outer member 14 and protuberances 18. However, the contact 16 may be positioned at a spot between adjacent protuberances, such as shown in phantom line 16 in FIG. 3, wherein only rolling contact is made with the outer member 14.

The inner and outer members 12 and 14 are secured to the dielectric base element 20 by any suitable means such as screws 21. An electrical terminal or lead 22 connects the inner member 12 with an electrical circuit such as shown in FIG. 4. Electrical lead 24 connects the outer member 14 with the electrical circuit to set-up the circuitry of the anti-disturbance switch 10. A dielectric base portion 26, having a cavity formed therein complementary with the outer member 14, is secured to the base member 20 by any suitable means such as screw 28 to provide a housing for the anti-disturbance switch 10. It is seen that the anti-disturbance switch is encapsulated within elements 20 and 26.

A switch in accordance with the invention is schematically shown installed in an illustrative firing circuit system, in FIG. 4. A circuit switch 31 is used to disengage a power supply or battery 30 from the circuit until the antidisturbance switch 10 is in place at which time the circuit switch 31 is closed. Specifically, a firing squib 36 is connected across the secondary 34 of a transformer 32. The operation of the FIG. 4 circuitry is such that a change in the initial contact relationship with respect to circuit elements 16 and 18 causes a surge of current in secondary 34 and therefore in squib 36, whereby the squib is fired. That is to say, if ball or contact member 16 is initially out of contact with dimple 18, this surge current will be caused to flow when ball 16 touches a dimple 18. On the other hand, let it be supposed that the elements 16 and 18 are initially in a closed circuit relationship, with ball 16 touching a dimple 18. If this closed circuit relationship is disturbed and the circuit is opened by reason of ball 16 rolling out of contact with dimple 18, then also under this circumstance a surge current will flow through secondary 34 firing squib 36.

Let it be assumed that the elements 16 and 18 are in closed circuit. Under this hypothesis, the entire voltage of source 30 is across resistor 33 in series with primary 38 of transformer 32, because primary 38 is short-cir- 3 cuited. Now if the elements 16 and 18 be open-circuited with respect to each other, this means that a large part of the voltage of source 30 will be instantaneously applied across primary 38, causing a surge of current in secondary 34.

Conversely, let it be assumed that the elements 16 and 18 are initially in open-circuit relationship to each other and that a disturbance occurs, causing them to be in closed circuit relationship to each other. This would cause the voltage across primary 38 to collapse, i.e., suddenly he reduced to zero. This change of voltage across the primary 38 will result in a surge of current across secondary 34, firing the squib.

The above discussion assumes that, prior to the opening or closing of the elements 16 and 18, that the source 30 has been in the circuit sufficiently long to achieve a stable condition. The discussion assumes that the squib 36 is protected against any transients that may be involved in initiating the supply of voltage from source 30. It is conventional practice in ordnance work to safe the squib 36 against undesired transients by a short-circuiting switch 37, which is opened by means well known in the art, such as at the time when a missile is launched.

In operation, the object or munition with the antidisturbance switch attached is deposited or placed in the desired operational position. When the electrical system is energized, the initial circuit state or path between the inner and outer members is either open or closed depending upon the position of the contact member 16 between them due to the attitude of the switch. Either initial position is acceptable in the operation of this switch.

Once the electrical system has been energized, any attempt to disarm or reorient the object or munition will result in movement of the rolling contact which will reverse the original contact status assumed when the switch is at the at-rest position. The electrical circuit will detect the reversal of status and provide a command signal, which may be a detonation command or an alarm signal, to a central control point or monitor that the object or munition has been disturbed from its original position.

The illustrative embodiment described shows the antidisturbance device as having a hemispherical shape. This hemisphere will allow the object or munition to be positioned or set up nearly ninety degrees from the normal horizontal, in any plane, and still the device will function. However, it is unlikely that the mounting position would vary from the horizontal more than ten or fifteen degrees in any plane. This then will allow the inner and outer members to be made less than a full one hundred and eighty degrees (hemisphere). Depending upon the original placement of the object or munition the angle of the function of the rolling contact may be such that only ninety degrees of included angle is required and the inner and outer contact members need not be complete hemispheres. In such cases the size of the device can be reduced accordingly, i.e., the inner and outer members need only be a segment of the hemisphere.

Also, it is possible to make the members ((inner and outer) completely spherical so that the device would function in three hundred and sixty degrees in any plane. This embodiment is illustrated in FIG. 5. The elements of FIG. correspond to similar elements shown in FIG. 3 and are designated by the same reference numeral followed by the letter designation a. This embodiment operates and functions the same as the hemispheric switch previously described and need not be described again. In addition, two or more units of the illustrative embodiment shown in FIGS. 1-3 can be placed in opposition to one another to provide the three hundred and sixty degree function.

The sphere 16 is made of a magnetic material so that attempts to disarm or immobilize the switch through the use of a magnetic force will cause the sphere 16 to move from its initial position to function the electrical circuit. The inner and outer members, 12 and 14, and contact member 16 can be made of brass and steel and coated with gold or any other appropriate non-corrosive and slow oxidizing metal to increase the shelf-life of the switch.

As will be apparent to those skilled in the art, the switch 10 can be made as sensitive as desired by increasing or decreasing the number of protuberances 18 on the inner member 12. If the number of protuberances 18 is reduced, then the ball 16 will have to travel a greater distance between the protuberances in order to make contact therewith, in other words, no change from a noncontact state to a contact state. The sensitivity of the switch can also be increased or decreased by changing the radial size of the inner and outer members. Thus, the shallower the spherical surfaces of the members are made, the more sensitive the device will be to disturbance. Conversely, as the configuration of the surfaces of the inner and outer members approaches a parabolic configuration, the sensitivity of the device tends to be reduced in the area of the closed end of the long axis. A parabolic configuration is shown in FIG. 6 in which the elements correspond to the same elements as described in FIGS. 1-3 and are designated by the same reference numeral followed by the letter designation b. This embodiment functions the same as previously described in regard to FIGS. l-3 and need not be described again. However, this may be a desired condition to overcome vibration problems in some cases. The weight of the rolling contact is also a determining factor in the sensitivity of the device. In reducing the overall size of the device to permit its use in small munitions it is also necessary to reduce the diameter of the rolling contact or ball being used. When reducing the diameter of the rolling contact, the more sensitive spherical-segment configuration of the inner and outer members may be incorporated. Conversely, when a larger diameter rolling contact (with more weight) can be used, the hemispherical or parabolic configuration of the inner and outer members may be incorporated.

The material used in the device is restricted only by the requirement that the working surfaces of the inner and outer members and the rolling contact or ball must be electrically conductive. It is only necessary that the raised or contact surfaces of the inner member be conductive. However, all of the raised or contact surfaces must be interconnected.

The illustrative embodiment disclosed shows that both the inner and outer members are stamped or drawn metal shells. An alternative method of manufacture is making the parts of plastic and plating the surfaces to secure electrical conductivity. Plastic molding may be less expensive in a development or small production contract since short-run molds can be made inexpensively and plating of the parts is not dependent upon the size of design.

The configuration of the protuberances on the inner member may vary due to the material being used, the metsod of producing the configuration, the space available, etc.

The protuberances 18 shown in the drawings are seen to be integral dimples which are stamped, drawn or fabricated with the inner member. However, other methods and means can be used to provide the protuberances. In one example, holes were drilled into the inner member and standard steel drive screws were inserted therein to provide the contact points. Instead of spherical shapes, the contacts may be made as frustums of cones in order to control the contact point of the ball. It would also be possible to have the contacts as pins or cylinders projecting from the inner member. The shape of the protuberances will be dependent upon the method of manufacture and the size of the device.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to those precise forms of apparatus.

What is claimed is:

l. An anti-disturbance switch comprising:

a first conducting member having a plurality of outwardly projecting protuberances in spaced apart relationship thereon,

a complementary second conducting member spaced from the first conducting member,

said second member providing a smooth rolling sur-- face,

mounting means for maintaining said first and second conducting members in spaced relationship to define a raceway therebetween, the raceway being interrupted by the protuberances and thereby defining a plurality of paths,

a single rolling contact member in continuous contact with the rolling surface of said second member and confined in the raceway defined by said members so that a mechanical disturbance of the switch affects the contact relationship between said contact member and one of said protuberances, and

means for providing terminal connections to said first and second members so that the contact member can perform a switching function.

2. An anti-disturbance switch comprising:

a housing,

a conducting inner member having a shape generally defined by a curvilinear surface of revolution mounted on said housing, said member having a plurality .of outwardly projecting protuberances in spaced apart relationship thereon,

a conducting outer member providing a smooth rolling surface and having a shape complementary with said inner member, said outer member mounted on said housing and over said inner member in spaced relationship therewith, wherein a plurality of paths are defined between the inner and outer members by the outwardly projecting protuberances,

a single rolling contact member free to move in any direction between said inner and outer members, said contact member being in continuous engagement with the outer member and of a sufficient size to contact the outwardly projecting protuberances depending on the attitude of the anti-disturbance switch wherein a disturbance of the switch affects the contact relationship between said contact member and one of the protuberances, and

an electrical circuit connected to said inner and outer members wherein said circuit assumes an initial state depending on the contact relationship between the rolling contact member with one of the protuberances of said inner member, said circuit providing a command signal in response to a change in the contact relationship of the contact member and one of the protuberances from the initial contact relationship.

3. An anti-disturbance switch as set forth in claim 2 wherein said outer member has a shape further defined by a curvilinear surface of revolution of greater radius than the corresponding surface of said inner member,

a first electrical lead connecting said inner member and said electrical circuit, and

a second electrical lead connecting said outer member and said electrical circuit, and said switch further comprising a dielectric housing in which said inner and outer members are mounted, said housing encapsulating said members so as to electrically isolate the members from an external object.

4. An anti-disturbance switch as set forth in claim 2 in which said inner and outer members are hemispheric in shape, the outer hemispheric shape being of a greater radius than the inner hemispheric shape, said hemispheric shapes permitting the anti-disturbance switch to be positioned at a maximum substantially ninety degrees from the normal horizontal in any plane and still functron.

5. An anti-disturbance switch as set forth in claim 2 in which said inner and outer members are spherical in shape, the outer spherical shape having a greater diameter than said inner spherical shape, said spherical members permitting the anti-disturbance switch to function in three hundred and sixty degrees in any plane.

6. An anti-disturbance switch as set forth in claim 2 in which said inner and outer members are each in the shape of a segment of a sphere, the outer spherical segment having a greater radius than the inner spherical segment.

7. An antiaiisturbance switch as set forth in claim 2 in which said inner and outer members are each in the shape of a paraboloid, the outer member having a greater radii eccentricity than the inner member.

8. An anti-disturbance switch comprising:

a first inner conducting member having a plurality of outwardly projecting protuberances in spaced apart relationship thereon,

a second outer conducting member spaced from the first conducting member, said second member providing a smooth rolling surface,

mounting means for maintaining said first and second conducting members in spaced relationship and defining a raceway therebetween, the raceway being interrupted by the protuberances,

a single rolling contact member in continuous contact with the rolling surface of said second member and confined in the raceway so that a mechanical disturbance of the switch affects the contact relationship between said contact member and one of said protuberances, and

an electrical circuit being connected to said inner and outer members wherein said circuit assumes initial state depending on the position of the rolling contact member with regard to a protuberance on said inner member which is established by the attitude of the switch, said circuit providing a command signal in response to a change from the initial state condition caused by the reorientation of the switch from the first attitude position.

9. An anti-disturbance switch as set forth in claim 8 in which said outwardly projecting protuberances are dimples formed on the inner member, said dimples being equally spaced about said member,

a first electrical lead connecting said inner member and said electrical circuit, and

a second electrical lead connecting said outer member and said electrical circuit.

10. An anti-disturbance switch as set forth in claim 9 in which said inner and outer members are made of brass and the rolling contact member is a conducting steel ball, and wherein there is a housing comprising a dielectric base to which said inner and outer members are mounted and a dielectric casing, said casing being formed with a configuration complementary with the outer member to form an exterior casing for said anti-disturbance switch when attached to said dielectric base.

References Cited UNITED STATES PATENTS 1,771,905 7/1930 Uher. 2,972,026 2/1961 Kendall 102-702 XR 3,103,120 9/1963 Tinney 200-61.45 XR 3,372,253 3/1968 Baker et a1. ZOO-61.45

ROBERT K. SCHAEFER, Primary Examiner M. GINSBURG, Assistant Examiner U.S. Cl. X.R. 

